1 Answer

Remember, the size of aggregate never be the same in a given sample. Suppose, Consider a bag labeled 20mm aggregate. All the aggregates present in this bag don’t have the size exact 20mm.

Maximum Size of Aggregate:

The smallest size of sieve through which entire amount of aggregate can pass through it.

Ex: Take 400g sample of 20mm aggregate. This 20mm aggregate can easily pass through the sieve of 25mm, 30mm, 40mm, 50mm….. because the size of 20mm is lesser than above sieves. In this scenario, the smallest size of sieve through which 20mm aggregate can pass is 25mm. Therefore, the maximum size of aggregate is 25mm.

Nominal Size of Aggregate:

The smallest size of sieve through which entire amount of aggregate can pass through it. But it may retain 10% of total weight of aggregate.

Ex: Take 400g of 30mm aggregate and allow it pass through 30mm sieve. In this scenario, the aggregate smaller or equal to 30mm will pass through the sieve and rest of aggregate which are bigger than 30mm retains on sieve. If the amount of aggregate retained on sieve is less than 10% of total weight of aggregate then the nominal size of aggregate is 30mm

Important Note: In sieve analysis, Dont take aggregate sample more than 400g.